High-pressure crystallography of rhombohedral PrAlO <sub>3</sub> perovskite

Zhao, Jing and Ross, Nancy L and Angel, Ross J and Carpenter, Michael A. and Howard, Christopher J. and Pawlak, Dorota A and Lukasiewicz, Tadeusz (2009) High-pressure crystallography of rhombohedral PrAlO <sub>3</sub> perovskite. Journal of Physics: Condensed Matter, 21 (23). p. 235403. DOI https://doi.org/10.1088/0953-8984/21/23/235403

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The evolution of the crystal structure of rhombohedral PrAlO3 perovskite with pressure has been investigated by single-crystal x-ray diffraction and Raman scattering experiments. The structural evolution as indicated by lattice strains, octahedral tilts, and the distortions of the octahedral AlO6 and polyhedral PrO12 groups with increasing pressure, is controlled by the relative compressibilities of the AlO6 octahedra and the PrO12 site. Because the AlO6 octahedra are more compressible than the PrO12 sites, up to 7.4 GPa the structure evolves towards the high-symmetry cubic phase like any other rhombohedral perovskite. The variation of volume of the rhombohedral phase with pressure can be represented by a third-order Birch–Murnaghan equation of state with bulk modulus K0 = 193.0(1.2) GPa and K' = 6.6(4). Above 7.4 GPa the evolution towards a cubic phase is interrupted by a phase transition. Observations are consistent with the assignment of Imma symmetry to the high-pressure phase. Comparison with the low-temperature R\bar {3}c to Imma transition confirms that electronic interactions stabilize the Imma phase.

Item Type: Article
Uncontrolled Keywords: 09AREP; IA58;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 21
Page Range: p. 235403
Identification Number: https://doi.org/10.1088/0953-8984/21/23/235403
Depositing User: Sarah Humbert
Date Deposited: 30 Apr 2010 14:14
Last Modified: 23 Jul 2013 09:57
URI: http://eprints.esc.cam.ac.uk/id/eprint/1375

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